Rapid and quantitative detection of Shiga toxin1 and Shiga toxin2 based on multiple targets UPT-LF assay

Qiaozhen Wei; Qiushi Hu; Fengjuan Shi; Shuang Li; Chongsi Sun; Huicong Zhang; Lei Xue; QiuXia Feng; Jinying Dong; Yongjun Jiao; Lei Zhou

doi:10.1002/elsc.202000031

Rapid and quantitative detection of Shiga toxin1 and Shiga toxin2 based on multiple targets UPT-LF assay

Eng Life Sci. 2020 Jul 19;20(11):494-503. doi: 10.1002/elsc.202000031. eCollection 2020 Nov.

Authors

Qiaozhen Wei^{1

2}, Qiushi Hu¹, Fengjuan Shi³, Shuang Li¹, Chongsi Sun¹, Huicong Zhang¹, Lei Xue¹, QiuXia Feng¹, Jinying Dong¹, Yongjun Jiao³, Lei Zhou¹

Affiliations

¹ National Key Laboratory of Biochemical Engineering PLA Key Laboratory of Biopharmaceutical Production & Formulation Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing P. R. China.
² The Department of Blood Transfusion The Second Affiliated Hospital of Anhui Medical University Hefei P. R. China.
³ Institute of Pathogenic Microbiology Jiangsu Provincial Center for Disease Prevention and Control Nanjing P. R. China.

Abstract

Shiga toxin-producing Escherichia coli (STEC) infection causes a series of diseases that are highly pathogenic and deadly in humans and animals, seriously endangering public health. Of the pathogenic factors within STEC, the two groups of Shiga toxin (Stx) consisting Stx1 and Stx2 plays a prominent role in the pathogenesis of STEC infection. In this study, we developed single-target up-converting phosphor technology-based lateral flow assay (Stx-UPT-LFA) for the rapid detection of Stx1 and Stx2, respectively, and also developed a dual-target Stx1/2-UPT-LFA based on single-target strips to detect of Stx1 and Stx2 at the meantime within 20 min. We choose the purified Stx1 and Stx2 standard samples, and the optimum monoclonal antibody (namely 8E7-E6, 2F6-F8 for Stx1 and S1D8, S2C4 for Stx2) were selected for use in Stx-UPT-LFA in double-antibody-sandwich mode. The sensitivities of single-target Stx-UPT-LFA for both Stx1 and Stx2 were 1 ng mL^-1 with accurate quantitation ranges of 1-1000 ng mL^-1 and 1-800 ng mL^-1 respectively. No false-negative result was found in the Stx2-UPT-LFA even with a high-test concentration up to 1000 ng mL^-1. Meanwhile, both targets detection sensitivities for dual-target Stx1/2-UPT-LFA were 5 ng mL^-1, and accurate quantitation ranges were 5-1000 ng mL^-1 and 5-800 ng mL^-1 for standard Stx1 and Stx2 solutions without cross-interference between two targets. Both techniques showed good linearities, with a linear fitting coefficient of determination(r) of 0.9058-0.9918. Therefore, the UPT-LFA could realize simultaneous detection for multiple targets on a single strip and thus to quickly determine the type of infectious Stxs. In addition, the single-target Stx1-UPT-LFA and Stx2-UPT-LFA showed excellent specificity to six toxins, even at high concentrations of 1000 ng mL^-1. In conclusion, the developed Stx-UPT-LFA allows the rapid, quantitative, reliable and simultaneous detection of Stx1 and Stx2 within 20 min, providing an alternative method for clinical diagnosis of STEC infection.

Keywords: Shiga toxin; dual‐target; lateral flow assay; single‐target; up‐converting phosphor technology.